134 lines
7.4 KiB
Plaintext
134 lines
7.4 KiB
Plaintext
/**
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@page EEPROM_Emulation application to show an eeprom emulation
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@verbatim
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******************* (C) COPYRIGHT 2016 STMicroelectronics ********************
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* @file EEPROM_Emulation/readme.txt
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* @author MCD Application Team
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* @brief Description of the EEPROM_Emulation application.
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******************************************************************************
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*
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* @attention
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*
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* Copyright (c) 2017 STMicroelectronics.
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* All rights reserved.
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*
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* This software is licensed under terms that can be found in the LICENSE file
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* in the root directory of this software component.
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* If no LICENSE file comes with this software, it is provided AS-IS.
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*
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******************************************************************************
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@endverbatim
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@par Application Description
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This application describes the software solution for substituting standalone EEPROM
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by emulating the EEPROM mechanism using the on-chip Flash of STM32F7xx devices.
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Please refer to AN3969 for further details regarding this application.
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The application requires two Flash memory sectors of identical size allocated to non-volatile data:
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one that is initially erased, and offers byte-by-byte programmability; the other that is ready
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to take over when the former sector needs to be garbage-collected. A header field that occupies
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the first half word (16-bit) of each sector indicates the sector status. Each of these sectors is
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considered as a page.
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The sectors used are Sector 2 and Sector 3 with a size of 32KB each one.
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STM327x6G-EVAL's LEDs can be used to monitor the application status:
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- LED1 is toggle when the example runs successfully.
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- LED3 is toggle in case of error.
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@note Care must be taken when using HAL_Delay(), this function provides accurate delay (in milliseconds)
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based on variable incremented in SysTick ISR. This implies that if HAL_Delay() is called from
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a peripheral ISR process, then the SysTick interrupt must have higher priority (numerically lower)
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than the peripheral interrupt. Otherwise the caller ISR process will be blocked.
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To change the SysTick interrupt priority you have to use HAL_NVIC_SetPriority() function.
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@note The application need to ensure that the SysTick time base is always set to 1 millisecond
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to have correct HAL operation.
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@par Keywords
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EEPROM, Emulation, Flash, Program, Erase, Sectors, OPCODE
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@Note<74>If the user code size exceeds the DTCM-RAM size or starts from internal cacheable memories (SRAM1 and SRAM2),that is shared between several processors,
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<20><><EFBFBD><EFBFBD><EFBFBD>then it is highly recommended to enable the CPU cache and maintain its coherence at application level.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>The address and the size of cacheable buffers (shared between CPU and other masters) must be properly updated to be aligned to cache line size (32 bytes).
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@Note It is recommended to enable the cache and maintain its coherence, but depending on the use case
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> It is also possible to configure the MPU as "Write through", to guarantee the write access coherence.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>In that case, the MPU must be configured as Cacheable/Bufferable/Not Shareable.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Even though the user must manage the cache coherence for read accesses.
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4838 <20>Managing memory protection unit (MPU) in STM32 MCUs<55>
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<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Please refer to the AN4839 <20>Level 1 cache on STM32F7 Series<65>
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@par Directory contents
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- EEPROM_Emulation/Inc/stm32f7xx_hal_conf.h HAL Configuration file
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- EEPROM_Emulation/Inc/main.h Header for main.c module
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- EEPROM_Emulation/Inc/eeprom.h Header for eeprom.c module
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- EEPROM_Emulation/Inc/stm32f7xx_it.h Header for stm32f7xx_it.c
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- EEPROM_Emulation/Src/main.c Main program
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- EEPROM_Emulation/Src/eeprom.c EEPROM program
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- EEPROM_Emulation/Src/stm32f7xx_it.c Interrupt handlers
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- EEPROM_Emulation/Src/system_stm32f7xx.c STM32F7xx system clock configuration file
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@par Hardware and Software environment
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- This example runs on STM32F756xx/STM32F746xx devices.
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- This example has been tested with STM327x6G-EVAL board revB and can be
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easily tailored to any other supported device and development board.
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Table 1. EEPROM application implementation on STM327x6G-EVAL RevB
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/*** Platform ***|************* Implementation **************************|***** Configuration *****\
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****************************************************************************************************
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| Firmware | The EEPROM program is located at 0x08000000. The Flash| |
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| | routines (program/erase) are executed from the Flash | |
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| | memory. | |
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| | The size of this program is about 6 Kbytes and | |
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| | programmed on: | Sector 0 |
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| | ------------------------------------------------------|-------------------------|
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| | | |
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| | The flash zone used for the EEPROM emulation is | 64KB |
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| | located at 0x08010000 | (Sector 2- Sector3) |
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| | | |
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\**************************************************************************************************/
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Following picture illustrates the situation in program memory:
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Top Flash Memory address /-------------------------------------------\ 0x080FFFFF
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| |
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| |
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| |
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| Sector 4 - Sector 7 |
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| |
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|-------------------------------------------| 0x08020000
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Sector 3 (32KB) | |
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| |
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| Flash used for EEPROM emulation mechanism | 0x08018000
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Sector 2 (32KB) | |
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| |
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|-------------------------------------------| 0x08010000
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Sector 1 (32KB) | |
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| |
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|-------------------------------------------| 0x08008000
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| |
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Sector 0 (32KB) | flash used for implement the EEPROM |
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| emulation mechanism(6KB) |
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\-------------------------------------------/ 0x08000000
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@par How to use it ?
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In order to make the program work, you must do the following :
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- Open your preferred toolchain
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- Rebuild all files and load your image into target memory
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- Run the example
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*/
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